<!DOCTYPE html>
<html>
<meta name="content-type" content="text/html; charset=UTF-8">
<head>
    <title>Calculator</title>
    <!--将按键内容以字符串形式存储在文字框中当按钮为“=”时，调用eval方法计算结果然后将结果输出文字框中-->
    <script type="text/javascript">
        var numresult;
        var str;
        function onclicknum(nums) {
            str = document.getElementById("nummessege");
            str.value = str.value + nums;
        }
        function onclickclear() {
            str = document.getElementById("nummessege");
            str.value = "";
        }
        function onclickresult() {
            str = document.getElementById("nummessege");
            numresult = eval(str.value);
            str.value = numresult;
        }
    </script>
</head>
<body bgcolor="affff" >
<!--定义按键表格,每个按键对应一个事件触发-->
<table border="1" align="center" bgColor="#bbff77"
       style="height: 350px; width: 270px">
    <tr>
        <td colspan="4">
            <input type="text" id="nummessege"
                   style="height: 90px; width: 350px; font-size: 50px" />
        </td>
    </tr>
    <tr>
        <td>
            <input type="button" value="1" id="1" onclick="onclicknum(1)"
                   style="height: 70px; width: 90px; font-size: 35px">
        </td>
        <td>
            <input type="button" value="2" id="2" onclick="onclicknum(2)"
                   style="height: 70px; width: 90px; font-size: 35px">
        </td>
        <td>
            <input type="button" value="3" id="3" onclick="onclicknum(3)"
                   style="height: 70px; width: 90px; font-size: 35px">
        </td>
        <td>
            <input type="button" value="+" id="add" onclick="onclicknum('+')"
                   style="height: 70px; width: 90px; font-size: 35px">
        </td>
    </tr>
    <tr>
        <td>
            <input type="button" value="4" id="4" onclick="onclicknum(4)"
                   style="height: 70px; width: 90px; font-size: 35px">
        </td>
        <td>
            <input type="button" value="5" id="5" onclick="onclicknum(5)"
                   style="height: 70px; width: 90px; font-size: 35px">
        </td>
        <td>
            <input type="button" value="6" id="6" onclick="onclicknum(6)"
                   style="height: 70px; width: 90px; font-size: 35px">
        </td>
        <td>
            <input type="button" value="-" id="sub" onclick="onclicknum('-')"
                   style="height: 70px; width: 90px; font-size: 35px">
        </td>
    </tr>
    <tr>
        <td>
            <input type="button" value="7" id="7" onclick="onclicknum(7)"
                   style="height: 70px; width: 90px; font-size: 35px">
        </td>
        <td>
            <input type="button" value="8" id="8" onclick="onclicknum(8)"
                   style="height: 70px; width: 90px; font-size: 35px">
        </td>
        <td>
            <input type="button" value="9" id="9" onclick="onclicknum(9)"
                   style="height: 70px; width: 90px; font-size: 35px">
        </td>
        <td>
            <input type="button" value="*" id="mul" onclick="onclicknum('*')"
                   style="height: 70px; width: 90px; font-size: 35px">
        </td>
    </tr>
    <tr>
        <td colspan="2">
            <input type="button" value="0" id="0" onclick="onclicknum(0)"
                   style="height: 70px; width: 190px; font-size: 35px">
        </td>
        <td>
            <input type="button" value="." id="point" onclick="onclicknum('.')"
                   style="height: 70px; width: 90px; font-size: 35px">
        </td>
        <td>
            <input type="button" value="/" id="division"
                   onclick="onclicknum('/')"
                   style="height: 70px; width: 90px; font-size: 35px">
        </td>
    </tr>
    <tr>
        <td colspan="2">
            <input type="button" value="Del" id="clear"
                   onclick="onclickclear()"
                   style="height: 70px; width: 190px; font-size: 35px" />
        </td>
        <td colspan="2">
            <input type="button" value="=" id="result"
                   onclick="onclickresult()"
                   style="height: 70px; width: 190px; font-size: 35px" />
        </td>

    </tr>

</table>
</body>
</html>